co-ˈploughing [co- 1, 3 a.] Co-operative ploughing; = co-aration. 1883Seebohm Eng. Vill. Commun. iv. iii. 121 And those who join in co-ploughing must bring a proper contribution.Ibid. 124 According to the Welsh laws it [the erw or acre] was the measure of a day's co-ploughing.